Cover Page - shares	3 Months Ended
	Mar. 31, 2023	Apr. 28, 2023
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2023
Document Transition Report	false
Entity File Number	001-40923
Entity Registrant Name	FRANKLIN BSP REALTY TRUST, INC.
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	46-1406086
Entity Address, Address Line One	1345 Avenue of the Americas
Entity Address, Address Line Two	Suite 32A
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10105
City Area Code	212
Local Phone Number	588-6770
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		82,280,994
Entity Central Index Key	0001562528
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q1
Entity Filer Category	Large Accelerated Filer
Amendment Flag	false
Common Stock
Document Information [Line Items]
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	FBRT
Security Exchange Name	NYSE
Series E Preferred Stock
Document Information [Line Items]
Title of 12(b) Security	7.50% Series E Cumulative Redeemable Preferred Stock, par value $0.01 per share
Trading Symbol	FBRT PRE
Security Exchange Name	NYSE